Surfactant. A synthetic detergent made from petrochemicals that lowers the surface tension of water and allows better cleaning in small spaces.
Do you have a cleaning issue that requires you to use a surfactant? If so, be aware that you must clean the surfactant in additon to your flux residue. The wetting agents and surfactants are non-ionic materials that are not detected by the Omegameter [or Ionigraph], which only measures the concentration of the ionic materials that are soluble in a alcohol-water solution.
However, these non-ionic residues tend to attract and absorb water onto the surface of the board. As the water is absorbed, it polarizes. When a voltage deferential is applied across two adjacent traces, the water ionizes forming a plating solution and dendrites can grow and develop a short. So, even though your board appears clean according to the Omegameter [or Ionigraph], it is actually a potential problem when it gets to the field.
Your washer and RO suppliers may be good starting points for your search.
[NOTE: The current thread on hand lotions is a nice analog to this thread.]
reply »